Plate type heat exchanger



May 3, 1949. J. F. BELAIEFF 2,469,028

PLATE TYPE HEAT EXCHANGER Filed Dec. 21, 1944 3 Sheets-Sheet 1 y 1949.J. F. BELAIEFF 2,469,028

PLATE TYPE HEAT EXCHANGER Filed Dec. 21, 1944 v 3 Sheets-Sheet 2arrow/vs J. F. BELAIEFF PLATE TYPE HEAT EXCHANGER May 3, 1949.

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Patented May 3, 1949 PLATE ma nan axcmmcen James Frank Belaiefl, London,

England, assignor of two-thirds to Cyril Terence Delaney and Gallay,Limited, London,

of Great Britain Application December 21, 1944, Serial No. In GreatBritain January 17, 1944 England, a company 2 Claims. (Cl. 257-139) Thisinvention relates to secondary surface heat exchange apparatus and inparticular to apparatus comprising a heat exchange unit for oil or otherviscous fluid in combination with a heat exchange unit for water, glycolor other fluid of a less viscous nature, and in particular to appara-tusof annular or segmental formembodying arcuate tubes which vary in lengthaccording to the radius of the arc. The expression secondary surfacemeans any surface conductively associated with the skin of the tube forthe liquid to be cooled so as to increase the efiective area availablefor the dissipation of heat.

One of the principal difficulties experienced in the design of suchradiators is to arrange for the tubes of the unit for the oil or otherviscous fluid to be all of the same length since coolers for such fluidwhich embody tubes of difiering lengths usually sufier from thephenomena known as coring due to unequal flow resistance.

By coring is meant the phenomena produced by over cooling when the oilcongeals on the cooling surface thus reducing the cross sectional areaof the cooling passage until the flow through such passage finallystops. This usually takes place irregularly throughout the matrix sothat parts only of the cooler are put out of action.

According to the present invention the tubes for the oil or otherviscous fluid are all constructed to be of the same length and all ormost are associated with a complementary tube for the water glycol orother less viscous fluid forming a continuation thereof to complete thearc of the annulus or segment whereby all available space is utilised.

In order that the invention may be more clearly understood referencewill now be made to the accompanying drawings, wherein,

Fig. 1 is a diagrammatic elevation of one form of arcuate secondarysurface heat exchange apparatus made according to the present inventioncomprising a combined oil cooler and water radiator for an aircraft and,

Fig. 2 is a section through the developed water and oil tubes shown inFig. 1. I

Fig. 3 is a fragmentary perspective view partly in section, showingdetails of the radiator shown in Fig. 1.

Fig, 4 is a perspective view of a modified form of radiator madeaccording to the present invention.

In the form shown the arcuate radiator is made up of a munber ofalternate long and short water tubes I, 2 and oil tubes 3.

Suitable inlet and outlet header tanks 4, 5. 6, I

respectively, are the water tubes arc and the header tanks 6, I for theoil tubes 3 at the other. The water tube I extends for the full areright up to the oil header tank' 6, I but the oil tubes all stop shortof the header tanks 4, 5 for the water tubes. In order to fill up thegaps left at the end of each oil tube 3 (shown in the drawing as a solidline to make them more easily distinguishable) and make the most use ofthe area available complementary arcuate short water tubes 2 areprovided each forming a continuation of the corresponding oil tube 3 soas to complete the arc and these shortened water tubes 2, all of whichare of difierent lengths according to the radius of the arc to which itis formed are mounted in the header tanks 4, 5 for the water tubes. Inorder to keep the header tanks 4, 5 for the water tubes and header tanks6, I for the oil tubes completely separate from one another and to avoidany possibility of leakage taking place from one tothe other, the tubesare divided lengthwise into flow arate inlet and outlet header tanks areprovided though a single header tank could be employed which is dividedinto inlet and outlet portions suitable couplings for connecting to theflow and return conduits being provided. The details of construction ofthe radiator shown diagrammatically in Figs. 1 and 2 are to be seen inFig. 3 andit is to be understood that no novelty is claimed for thebracing of the tubes or the arrangement of flow and return passageswithin the tubes.

Referring to Fig, 3 it will be seen that the oil tubes 3 all of equallength open above the tube plate 2' whilst the long water tubes I areclosed at the end adjacent the plate 2'. The plate 2' forms the bottomof the header tanks 6 and 1 for the oil or other viscous fluid. Thesheet metal internal and external bracing of the tubes technicallytermed secondary surfaces follows normal radiator construction, as shownfor example in Patent No. 2,376,749 to the present applicant. Theexternal bracing comprises corrugated metal sheets 8 between the tubesand the internal bracing comprises corrugated metal sheets 9, I0 and IIwithin the tubes the corrugations being arranged to divide the tube intoflow and return passages in the sheets 9 and I II and transversecommunication passages in the sheet II which construction is alreadyknown. This arrangement is shown clearly in the development shown inFig. 2.

The corrugated metal sheets and the inner and outer surfaces of thesheets of which the tubes and return passages and separe formed arecoated with solder before assembly and following the usual methods theassembled unit is *heated to cause the solder to melt and bond the wholeinto a single unit as well as sealing the folded seams. The return flowarrangement of the corrugations of the internal secondary surface isseen more clearly in Fig. 2 which shows one of the oil and water tubeseach with one side removed. The tubes are all braced internally and heldin spaced relation externally by corrugated secondary surfaces theexternal corrugated secondary surface forming air passages parallel withthe axis of the arc.

In the modified construction shown in Fig. 4 the same reference numeralsare applied to the same parts and accordingly the operation is the sameas with the construction shown in Figs. 1 to 3 and described withreference thereto. It is in fact as though an arcuate radiator such asis shown in Fig. 1 had been pulled out straight thereby assuming atrapezoidal instead of an arcuate form.

It must be understood that the present invention does not only refer toradiators of arcuate, circular or trapezoidal shape but may also beapplied to radiators of any shape in which some of the tubes have to beof varying length to occupy the available space.

With a heat exchange apparatus made as described above a more eflicientcooler for oil or other viscous fluid is obtained than withconstructions having tubes of varying length and it has been found thatwith the non-viscous fluid such as water the varying lengths of thetubes does not have any apparent detrimental efiect on the efficiency.The construction further is inexpensive and simple and makes thegreatest use of the available space.

What I claim and desire to secure by Letters Patent is:

1. Heatexchange apparatus comprising an assembly having inlet and exitheader means for relatively viscous fluid at one end thereof and inletand exit header means for less viscous fluid at the other end thereof,the distance of the assembly fromv end to end between opposite headermeans being less at one side of the same than at the other, a first setof tubes shorter than said lesser distance for the relatively viscousfluid extending lengthwise of the assembly parallel to each other someof the distance between said inlet and exit header means and connectedat one end to said first named inlet and exit header means, said tubesbeing closed at their ends re mote from said first named inlet and exitheader means and being divided internally into flow and return passages,and being all of the same length, and a second set of similarly formedtubes all of different lengths forthe less viscous fluid, extendinglengthwise of the assembly parallel to each other, from said lessviscous inlet and exit header means approximately to the closed ends ofsaid first named tubes and a third set of similarly formed tubes alsofor the less viscous fluid extending lengthwise of the assembly fromsaid less viscous inlet and exit header means between the tubes of saidsecond set and for the latter part of their extent between the tubes ofsaid first set approximately to said opposite header means.

2. Heat exchange apparatus comprising an assembly of arcuate shapehaving inlet and exit header means for relatively viscous fluid at one,end thereof and inlet and exit header means for less viscous fluid atthe other end thereof, a first set of arcuate tubes for the relativelyviscous fluid extending parallel some of the distance to each otherbetween said inlet and exit header means, from and connected at one endto said first named inlet and exit header means, said tubes being closedat their ends remote from said first named header means and beingdivided internally into flow and return passages, and beingall of thesame length, a second set of similarly formed arcuate tubes for the lessviscous fluid extending parallel to each other from said less viscousinlet and exit header means approxi: mately to the closed ends of saidfirst named tubes, and a third set of similarly formed arcuate tubes forthe less viscous fluid extending lengthwise of the assembly from saidless viscous inlet and exit header means between the tubes of saidsecond set and for the latter part of their extent towards the oppositeheader means between the tubes of said first set.

JAMES FRANK BELAIEFF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,329,697 Bowman Feb. 3, 19202,171,817 Wagner et al Sept. 5, 1939 2,175,432 Gerstung Oct. 10, 1939

